Robots are automated or autonomous devices that are able to manipulate objects using a series of rigid links, which in turn are interconnected via articulations or motor-driven robotic joints. Each joint in a typical robot represents an independent control variable, also referred to as a degree of freedom (DOF). End-effectors are the particular links used for performing a task at hand, e.g., grasping a work tool or other object. Therefore, precise motion control of a robot may be organized by the level of task specification: object level control, i.e., the ability to control the behavior of an object held in a single or cooperative grasp of a robot, end-effector control, and joint level control. Collectively, the various control levels cooperate to achieve the required robotic mobility, dexterity, and work task-related functionality.
Humanoid robots in particular have an approximately human structure, function, and/or appearance, whether a full body, a torso, and/or one or more appendages, with the required structural complexity of the humanoid robot being largely dependent upon the nature of the work task being performed. The use of humanoid robots may be preferred where direct interaction is required with objects, tools, or systems that are specifically intended for human use. Due to the wide spectrum of potential work tasks that may be expected of a humanoid robot, different control modes may be simultaneously required. For example, precise control must be applied within the different control spaces noted above, as well as over an applied torque, force, or resultant joint motion.
Conventional robotic systems may rely on task-specific end-effectors, part fixtures, and jigs to implement an assembly process. In some cases, machine vision systems may be implemented and tuned to locate a specific part, and/or to confirm completion of an assembly task or a sequential step thereof Setting up such a system may be relatively time consuming, and often requires extensive calibration, robot programming, and machine-level code compilation. State of the art machine vision systems may employ two-dimensional or three-dimensional vision systems and structured/engineered lighting techniques. The resulting assembly system may tend to be specific to just one set of like tasks and work conditions. Likewise, the set-up, commissioning, and support of the robot may be relatively challenging and time-consuming, with fixturing, tooling, and/or various material handling equipment normally required, thus resulting in added engineering, installation, and other expenses.